Flat bed and cylinder printing press



March 1956 w. G. MONTGOMERY ETAL 2,737,111

FLAT BED AND CYLINDER PRINTING PRESS Filed Oct. 25. 1951 5 Sheets-Sheet 1 FIG.

INVENTOR. h/llLl/IM 6. MONTGOMERY J/IMl/EL fl. HUFFMAN March 6, 1956 w. G. MONTGOMERY ETAL 2,737,111

FLAT BED AND CYLINDER PRINTING PRESS 5 Sheets-Sheet 2 Filed on. 23. 1951 \w w? 8 NQ nun Gum NW ab 0% n W hm mm mm March 6, 1956 w. e. MONTGOMERY ETAL 2,737,111

FLAT BED AND CYLINDER PRINTING PRESS Filed Oct. 23, 1951 5 SheetsSheet 3 uvmvroa WILL MM 6. MONTGOMERY ,mMuu ,4. HUFFMAN I 1047 f-i wvf' March 6, 1956 w. G. MONTGOMERY ETAL 2,737,111

FLAT BED AND CYLINDER PRINTING PRESS 5 Sheets-Sheet 4 Filed Oct. 23, 1951 INVENTOR. W/Zl/HM MON7'60M5KY .YflMl/EL A. HUFFMAN March 6, 1956 w; G. MONTGOMERY ET AL 2,737,111

FLAT BED AND CYLINDER PRINTING PRESS 5 7. LC a 2 *M e 8 TOM 4 m s 3 n NW 8 [NH 8 7. M fl. w r MM (J a l M "M B m P F r M V W m L b a w 7 H -im- FIG.

Filed Oct. 23. 1951 7 press.

during thereturn stroke.

'FLA T BED CYIJINDE-R PRINTING PRESS William Montgomery and Samuel A. Huffman, Marietta, Ohi;-said Hulfman assignor to said Montgomery Application October 23, 1951, Serial No.f25 2,642 21 Claims. (Cl. 101283) Ourinvention relates to a flat bed and cylinder printing It relates,.m'ore particularly, to a printing press of the-reciprocable bed and two revolution cylinder type. Itdea'ls, more specifically, with the cylinder structure, the cylinder driving means, and the cylinder raising and lowering means ofa press of the general type indicated.

This, application is a continuation-in-part of our copending application, Serial No. 197,218, filed November 24,1950.

In the-printing press disclosed in said copending application, the bed is reciprocated with a full harmonic motion, the impression cylinder is rotated in the same direction-at all times, regardless of direction of movement of the 'bed,;the :rotation of the cylinder is, timed with-the movement of the bed so that cylinder rotation and bed motion are in exact synchronism at all times, and the cylinder is in contact with the form carried bythe bed during movement of the bed in one direction, that is during -.the,printing stroke, but is lifted therefrom during movement of the bed in the opposite direction, thatuis, In the press disclosed in said d ates Patent application, the means for driving the printingcylinder iscompletely under the control of the bed-driving .means on -both,st rokes of the bed. Because of the simple harmonic bed motion, the movement of the bed starts and increases inspeed to a maximum and then "decreases until the bed stops at the endof the stroke. Since the cylinder-drive is under control of the bed motion, during each stroke ofthe bed the cylinder rotation starts with the stroke of the bed, increases to almaximum'and then is -decelerateduntilit stops at the end of the stroke of the bed.

-'It -.is; oneiof the main objects of ourinvention to provide an improved cylinder structure for a printing ,press of the-type-indicated which is so designed that it is extremely rigidiand will have substantially no deflection during the printing impression-and its design is such thatits drive by the; bed; motion in the manner indicated above is r-g reatly facilitated.

Another objectlof our-invention is to providea cylinder 'ofthe typeindicated which is so designed thatitincludes a minimum, oflstructure which must be accelerated and decelerated by the driving means and wherein this structure is light-in weight to facilitate acceleration and deceleration.

Another object of our invention is to provide a cylinder structured the type-indicated wherein very'simple means is associated therewith for raising and lowerirg the surface of the cylinder relative to theform carried by the bed.

Another object of our invention is .to provide a print ing press with a cylinder structure of the type indicated 1 a mor'epp'ositive drive at all times andqu'ieter operation. 1

According to the present invention, instead of making ice the impression cylinder; asa single large "unit complete with; the trunnions, which is very'rheavy and ditficultto rotate, as indicated above, we construct the-cylinder of several separate pieces. These pieces include the heavy trunnion or shaft and a shell which is :lightin weight and is mounted on the shaft, the: shaft being stationary and it being necessary; to rotate only-the shell, Thus, driving of the impression surfaceof the cylinder is:.greatly facilitated and the accelerationand deceleration thereof can be accomplished with ease; and with: simplemdriving means; This structure not: only facilitates driving but it also facilitates raising andrloweringof the impression i-shell" of t the cylinder which; can; be accomplished merely-'by providing a rotatable eccentric on the heavy shaftiand -between it and the outer, shell. The;-lightweigh=t=shell is; driven "in th6"Sam 6:dil'CIlQl1i='at all times .fromfthe bed-driving means by an improved clutch whichis mountedat one end, of the, 'cylinder s'truc- 'ture; andpwhich drives the cylinder shell driving gears that are concentric with thecylinde'r trunnion shaft :at all times. The drive from the-bed driving-means:to:the cylindershell :isthrough gears. which are constantly in mesh and which. havefixed centers. The use'of the heavy trunnion shaft anda separate impressionshell also results in .arcylinder structure which will have littleorno defiection'during theprintin'g operation when the cylinder is forced downz againstlthe printing form on. the'bedt/ The preferred embodiment of; our invention isai1lustrated in the accompanying drawings whereinrsimilar characters of reference designate corresponding ,parts and wherein;

Figure l is a-vertical sectional view throughaapr int- ,ing presspin which our invention has been embodied.

vFigure 2is an enlarged view of thecy-linder structure, partly. in elevation and partly in section.

Figure -3 .:is, a diagrammatic view illustrating. the drive from -the ,b'eddriving means 'to the cylinder shell driving means.

Figure 42is :anenlarged plan view of'theclutchmnitused inwdrivingthe cylinder shell.

figure 5 is ,a sectional view showing the .unit .of Figure 4:, the sectionwbeing taken substantially along .line 575 of Figure-2.

.Figure:6-is an end viewcf the'cylinder structure show- :ing the supporting means at: the end opposite to-"that where; the clutch; unit; is disposed.

Figure .7- is1aplan viewof the structure of Figure 6.

Figure 8 is .awertical sectional view :taken substantially alongllin'e 8-'-8,of Figure 2,and-.showing the eccentric means provided for raisingand lowering the cylinder-shell.

Figure 9 iswa vertical sectional view taken substantially alongdine 9-9 of Figure 2 and showing the; driving connection betweeu the, clutchunit and -zthe cylinderrshel'l.

.Figure l Ois-a -verticalsectional view. through the cylin- -der=- structure taken along line 10- 10 of Figure ,2.-

Figurell is a-view-similarto Figure :IO butzshoWi'ng -a=modification of the cylindershell.

general construction disclosed inaaid-copending application-,{Serial, No. 197,218,. This, press, includes; .thesfliame 15 which is provided with-the L'side :frame =nrembers;,.-1 6

and .11. Supported on, .this ;.frame arethe\becl-.tnippgor tirrg track.members; 18 and,19. These track,members lti 19 support the bed 20 for longitudinal reciprp tion.

The driving mechanism for the bed. 20 reciprocates with.

a full harmonic motion and includes a rack 21 which is carried by a Scotch yoke 22 that is shown in detail in said copending application and is reciprocated in the manner described therein. The rack 21 engages a pinion 23 carried-by the shaft 24 which is mounted for oscillation in the bearings 25 and 26 carried by portions of the frame 15. This shaft 24 is oscillated by the reciprocating movement of the yoke 22 and carries the bed driving gears 27 and 28 which'are keyed thereon. These gears 27 and 28 mesh with the bed driving racks 29 and 30.

The impression cylinder unit is carried by the frame 15 above the bed 20 for cooperation therewith. As previously indicated, this cylinder unit is so designed that it will-be substantially free of deflection during the printing impression and its design is such that its drive by the bed driving means is facilitated and the required driving power is a minimum. The cylinder unit comprises the heavy stationary trunnion shaft 36 and an outer impression shell 37 which is mounted thereon for rotation. The shell 37 is adapted to be driven in accordance with the bed motion while the heavy shaft 36 is always stationary. Thus, only the light-weight shell 37 need be driven. This shell 37 can be formed of light-weight material, such as aluminum, magnesium or titanium, to further facilitate driving thereof.

The shaft 36 is supported at one end in 'an upward extension 16a of the side frame member 16. This end of the shaft is reduced at 36a and is rigidly supported in the upper end of the portion 16a being retained in position by means of the cap 16b which is bolted in place by the bolts 38 and which is provided with a dowel pin 39 which extends into the reduced portion of the shaft to prevent rotation of the shaft.

The opposite end of the shaft 36 is mounted in the other side frame member 17. This end of the shaft 36 is provided with a reduced extension 36b. On this extension 36b is mounted a needle bearing 40 which rotatably carries a driving sleeve 41. The inner end of the sleeve 41 is bolted to a flanged driving sleeve 42 which extends radially and then inwardly over a stationary bushing 43 that is fixed to another reduced portion 36c of the shaft 36. As shown in Figures 2 and 9, the cylinder shell driving member 42 is provided with a radially extending lug 42a on which a roller 44 is mounted. This roller 44 fits between a pair of radially projecting lugs 45 carried on the end of the cylinder shell 37 which form a roller guide channel or slot. Thus, the connection between the cylinder shell driving member 42 and the cylinder shell is a roller and slot arrangement which will permit the necessary movement of the shell towards and away from the axis of the shaft 36 without disturbing the driving connection between the members 37 and 42.

The raising and lowering of the cylinder shell 37 to .bring about contact of the surface of the shell with the form carried by the bed 20 during the printing operation and spacing of these members on the return stroke is accomplished with an eccentric arrangement illustrated best in Figures 2, 8 and 10. This arrangement comprises an eccentric sleeve 46 which is rotatably mounted on the shaft 36'. The shell 37 is provided with a suitable number of circular bearings 47, which may be anti-friction bearings, if desired, which support the shell on the eccentric 46. One end of the eccentric sleeve 46 bears against the bushing 43 which is fixed to the shaft 36 while its other end bears against the upward extension 16a of the side frame member 16 and the cap 16b. Thus, axial .movement of the sleeve 46 is precluded. It will be noted from Figure 2 that the left hand end of the eccentric sleeve 46 projects beyond the end of the cylinder shell 37 and is provided with a thrust ring 48 formed thereon which prevents movement of the shell 37 to the left on the eccentric sleeve. Movement of the shell in the oppo' site direction on the sleeve is prevented by a thrust flange 49 which is formed on the inner end of the cylinder driving sleeve 42.

It will be apparent that by simply oscillating the eccen tric sleeve 46 on the stationary shaft 36, the shell. 37 will be moved towards and from the axis of the shaft 36, that is, it will be raised and lowered relative to the printing form carried by the reciprocable bed 20. This sleeve 46 can be oscillated by means of an adjustable link 50 which is pivoted to a radially extending arm 51 formed on the left hand end of the sleeve 46. The rod 50 may be reciprocated in timed relationship to the movement of the bed by suitable means (not shown).

As previously indicated, the cylinder shell 37 is driven from the bed driving means. The drive between the bed driving means and the shell driving sleeve 42 includes an improved clutch unit 52. This unit is illustratedbest in Figures 2, 4 and 5. 1

The clutch, 52 includes the gear 53 at one side thereof and the gear 54 at the other side thereof, both of which are mounted for oscillation and which are simultaneously oscillated but in opposite directions. The gear 53 is provided with an outwardly extending hub 55 which is mounted on a needle bearing 56 carried by the cylinder shell driving sleeve 41. Surrounding the hub 55 is a ballbearing 57 which is supported within the upper portion of the side frame member 17. The bearing 57 is mounted in the side frame member 17 so that axial movement of the bearing is precluded, as indicated, and is mounted on the hub 55 in such a manner that axial movement of the gear 53 is precluded. It will be noted that the gear 53 is substantially enclosed by an inwardly-extending guard 58 formed on the side member 17. The member 17 also carries a housing portion 59 which extends outwardly therefrom and which encloses the clutch mechanism including the gear 54. The outer side of this housing may be closed by a removable plate 60. The gear 54 carries a hub 61 which is mounted by means of a needle bearing 62 on a stub shaft 63 which is formed centrally of the plate and extends inwardly therefrom. The needle bearing 64 runs on hub 61 and supports a sleeve 65 which is threaded on the outer end of cylinder shell driving sleeve 41. Axial movement of the gear 54 is precluded by a flange 66 formed on the sleeve 65 and a ring 67 which is fixed to the gear 54 and overlaps the flange 66.

As indicated above, the gears 53 and 54 are both oscillated but they are oscillated in opposite directions. This oscillation is accomplished by means which will now be described. The gear 53 is oscillated directly from the bed 20 by means of a rack 68 which is carried at the upper side of the bed, as shown best in Figures 1 and 3, and which extends longitudinally thereof at the-one side thereof directly below the gear 53. Thus, when the bed 20 is reciprocated longitudinally, the gear 53 is oscillated. The gear 54 is oscillated by means of'an idler gear 69 which is carried on a stud 70 (Figure 1') carried by the side frame member 17 and projecting outwardly therefrom. The gear 69 meshes directly with the-gear 54 and with a gear 71 which is carried on the projecting'end 24a of the oscillatable bed driving shaft 24. It will be noted that because of the provision of the idler gear 69 between the gears 54 and 71, the gear 54 will be rotated in a direction opposite to the direction of rotation of the gear 53. Thus, both gears 53 and 54 rotate simultaneously but in opposite directions.

The clutch unit 52 includes a clutch arrangement for alternately connecting the gear 53 and the gear 54 with the cylinder shell driving sleeve 41. This connection is accomplished when the gears 53 and 54 are driven successively in the same direction. Thus, the cylinder shell 37 will always be driven in the same direction and in exact synchronism with the movement of the bed 20.

The clutch arrangement is illustrated best in Figures 2, 4, 5, 12 and 13. It will'be noted from Figure 2 that the outer edge of the hub 55 of the gear 53 is provided with clutch teeth 72 which are adapted to engage teeth 73 on the inner edge of a shifting collar 74 of th'e'clutch unit. Similarly, the ring "67 whichzis attachedto-thegfear 54fis;prov'ided with teeth 75 on its inner surface adapted to engage teeth'76 on the outer edge of a shifting collar 7.7. Both of the collars '74 and 77 are splin'ed to the sleeve 41 which drives the cylinder shell driving 'n'ie'mber 42. When the collar 74 is engaged with the gear '53, t'he drive is through the gear 53 and when the collar .77 is engaged with the gear 54, the drive is through the gear '54. Axial movement of clutch collars 74 and 77 toalternately engage the respective gears 53 and 54 is accomjp'lished with cam mechanism now to be described.

This mechanism comprises a pair of cams 78 which are carried on the opposite ends of a shaft 79. 'Thjis shaft 79 extends diametrically throughfthe sleeve *41 and is rotatably carried by it. For supporting the ends of the shaft 79, the sleeve carries the anti-friction bearing 80 "at opposite sides thereof. Carried by the clutch shifting collar '74 is a pair of opposed ca'rn followers 81wh'ich engage the respective cams 78 at the one side thereof and similarly carried by the shifting collar 77 is 'ap'air of cam 'fo llowers 82 which engage the respective earns 78 at the other side thereof. It will "be apparent that rotation'of shaft 79 about its axis will move the cdllars 74 and 77 axially. In order to keep the followers 81 and 82 in engagement with the respective cams '78,the "spring arrangement illustrated best in Figure 4 is provided. This spring arrangement comprises a pair ofdiametrica lly'op- 'p'osed compression springs 83. Each spring 83'isdispo'se'd between a collar 84 and a collar 85. The collar '84 is mounted on a sleeve 86 in engagement with a split ring '87. The opposite end of this sleeve 86' is provided with ar ing 8 8 which engages the outer side of alug 89formed on the clutch-shifting collar 77. The other collar "85 en'g'agedby spring 83 is provided with a 'U-s'hapeextension 90 which straddles the portion 89 and the outer edge (if-which engages the head '91 formedjon the adjacentend of a pin 92 which extends through a radially extending lug 93 on the clutch collar 74 and carries a split ring 94 which engages the outer side of clutch lu'g 93. The two spring units are identical, as indicated, except that they are "reversed. It will be apparent that with this arrangement although compression springs are provided, they will serve to move the rings 74 and '77 towards each -other and 'therebykeep the followers 81 and 82 in c'ont'aetwith the cams 78. i

The cam shaft 79 is driven by a constant-speed 'drive shaft 95 which extends through and is rotatably disposed in the 'oscilla'table shaft 36. The shaft 95 may be-dri-ven 'fromfits left hand end, which projects fro'mjt'he shift 36, by means of a suitable chain and sprocket drive 96 which extends from a suitable constant speed drive on the machine. The opposite or right hand 'end' of the *s'haft 95 has a bevel gear 97 keyed on an extensionthereof which projects from the extension 36b of theshaft 36. This beveled gear meshes with a bevel ge'ar-or' pinion- 98 which is keyed on the cam shaft 79adj'ac'ento'ne of the earns 78. Thus, it will be apparent that the eamshaft 79 is driven by the constant speedshaft'95.

The operation of the clutch unit 52 is 'as followsr With the clutches in the condition shown in Figure l2, that 'is, with the collar 74 in engagement with gea'r 53 'and the gear 54 will be driven in an opposite direction fby the gear 71 through idler gear 69; When the clutch-collar '77 engages the gear 54 and the clutch collar 74 is disengaged from the gear 53, the gear '54- drives the sleeve 41 and, therefore, the cylinder shell 37, and'thje gear '53; is free of the sleeve '41; Thiswill befduring ?the return stroke of the bed'and it will' be understo'bd that "the gear will be rdtat'ing in the same direction as 53 and 5 1. The constant speed shaft willdr ive the bevel gear 97 in the same direction as the cylinder shell driving. sleeve 41. There will be a differential action between, the two be ause of the variable speed of the "sleeve 41', resulting in the gear 917' rotating relative to the sleeve '41 and thereby rotating the 'bevel gear "98 about its axis which produeesrotation of the shaft 79 and the cams 78 carried 't'herebyi This rotation "of the cams will cause engagement of the 'two clutches at 'the proper intervals. As indicated in Figure 13-, at; the extre'rne "end of the stroke of "the bed, the cams 7.7 will be rotated to such a position "that 'both of'the clutchesfwill be engaged. The gearing is such and the differential action isjs'uch that this becrirs atthe end'o'f each stroke. Then as the bed reverses itself, one of the "clutches is disengaged and the other -is "engaged. Both clutches are in engagement at the end o'f'each stroke of "the bed because the "cam "is rotated through one-half revolution for each stroke. "thus, with the shape of the -'cam in'di- 'cated, the en agement ef "b'ot h clutches will occu'rat the end of'each s'troke.

As previously indica 'teri, the cylinder shell '37 is preferably composed of light-weight material, such 'as aluminum or magnesium 'or titanium. As indicated in Figure 2', it may'he rovided withrings-or bearers 1'00 which may be formed of more wear-resistant "material, such as' hardened steel or other suitable material. Tnsteadof merely having the wear-resistant rings 100, the entire printing surface of the shell 37' he covered with a S11E61? 101 Of :WCQFICSYS'IHHI llltitii al :35 shown in Figure 1-1, which is suitahly s'e'cnred thereto,

-It will be apparent "-fro'mt'he above description that we have provided a greatly improved c'ylinder structure "for a printing "press -'0'fthe general type i'ndic'ated. This proved cylinder StrtItt'Ire iS extremely l'igid Sb that it will be-fsubs'tant'i'ally 'fre'e -of deflection during the printing impression. Bb'alidedhd light-'Wlgh'flsh'cll isthe 'O'nly part of the cylinder which is-='driven-, the-eeceleration and deceleration ot the shell :is accomplished with ease as compared ii) 'the acceleration Qfnd dec'elldtibh 5f the heavy 0116-Pi8 prior art yli'l'idr' si fuctfir'e's. P'OiiIte'd' 'out in the cope'nding application fe'rreddo, this type of press is designed to opera' tea't very high speeds cornzpared fto previously manufactured 'presses. Since the press is designed to operate at a very high speed, the forcesof acceleration and deceleration are very great in driving a massive cylinder structure of the type used in the prior art. Therefore, our cylinderstructureiis particu'larly important in high speed Lpresses of the general type described in 'saidsa'pplication. Also, 'due to the particular cylinder structure which -we have provided, "the driving means has beenmsimplified and'only constantlyengaging driving gears having fixedcenters are employed. Furthermore, :the movement :of the :lighteweightcylinder shell is with a very simple eccentric arrangement.

Various other advantages will be apparent;

Having thus described our-invention, what we claimis:

1. In a flat'bed and-cylinder'printing press, a'reciprocable bed and an impression cylinder disposedin 'cooperative relationship, said cylinder including a trunnionsshaft and an --irhpression shell rotattably. mounted "on said sha'ft, means for reciprocati-ng' 'said bed with a full harmonic motion, andmeans opera-tivel-y connected to "said he'dreeiprocating means for driving-said hnpressidn shell 'in the-samedi'rection at allti'rh'sin "exact syhchronismwith the movement of the bed at an ti'nies'hnd'through two completerevolutions for each complete reciprocating cycle or the-bed, s'a id driving means for said shell, ineludinga shell driving-memberconnected to said 'shu so as to drive it, a pairdfbscillatabk *gejarstharere 1 oscillated oppositedirect'ion's by said-"bed-reeiprdcaiing bed-reciprocating means in the same direction to drive 3. Structure according to claim 2 wherein said cam mechanism includes a rotatable cam and means for ro- -tating said cam in timed relationship to the movement ,of the bed, said means rotating the cam so as to cause engagement of one clutch and disengagement of the other at the start of one stroke of the bed movement and engagement of both clutches at the end of such stroke.

4. A printing press according to claim 3 wherein the cam is so shaped that for each one-half revolution thereof, one clutch remains in engagement while the other clutch becomes disengaged and remains out of engagement for the major portion of the half-revolution and is again engaged just prior to the completion of the half-revolution. 5. Structure according to claim 4 wherein said bed is driven by a reciprocable rack, gearing connecting one of said oscillatable gears with said rack, said bed carrying a rack and driving the other of said oscillatable gears, said gearing always driving the one oscillatable gear in a direction opposite to that of the other oscillatable gear. 6. Structure according to claim 5 wherein said shell driving member includes a rotatable sleeve upon which both of said oscillatable gears are splined, clutch rings carried by the sleeve for axial movement thereof to engage the respective oscillatable gears, clutch-actuating mechanism comprising a cam carried by the sleeve for revolving movement with the sleeve, and means for rotating said cam to move said clutch rings axially into and out of engagement with said oscillatable gears.

7. Structure according to claim 6 wherein said means for rotating the cam comprises a constantly driven gear I disposed within said sleeve coaxial therewith and mounted 8. Structure according to claim 7 wherein the constantly driven gear is carried by a shaft extending through the trunnion shaft of said cylinder structure.

9. Structure according to claim 8 wherein said cylinder shell driving sleeve is disposed at one end of said cylinder shell and is coaxial with said trunnion shaft.

10. Structure according to claim 9 wherein a driving connection is provided between the sleeve and the shell, said connection comprising a roller on one of said members fitting into a radial slot in the other of said members.

11. Structure according to claim 10 wherein the shell is carried on the trunnion shaft by an intermediate eccentric sleeve, and means forrotating said sleeve.

12. In a flat bed and cylinder printing press, a reciprocable bed and an impression cylinder rotatable on a trunnion shaft and disposed in cooperative relationship with the bed, means for reciprocating said bed with a full harmonic motion, and means operatively connected to said bed-reciprocating means for driving said impression cylinder in the same direction at all times in exact synchronism with the movement of the bed at all times and through two complete revolutions for each complete reciprocating cycle of the bed, said means comprising a pair of oscillatable gears that are concentric with said cylinder trunnion shaft and are oscillated in opposite directions about the axis of said shaft, means for drivingsaid gears successively by said bed-reciprocating means in the same direction, and a clutch mechanism for alternately driving said cylinder from each of said oscillatable gears, said clutch mechanism including m'eansfor selectively connecting said cylinder to each of said gears in succession as the gears are driven successively by said bed-reciprocating means in the same direction to dr1vc saidcylinder in the proper direction.

'13. Structure according to claim 12 wherein said clutch mechanism comprises two clutches, one of said clutches being associated with one of said oscillatable gears and the other of said clutches being associated with the other of said oscillatable gears, and clutch-actuating means comprising cam mechanism which ensures that one of the clutches is in engagement before the other is released.

14. Structure according to claim 13 wherein said cam mechanism includes a rotatable cam and means for rotating said cam in timed relationship to the movement of the bed, said means rotating the cam so as to cause engagement of one clutch and disengagement of the other at the start of one stroke of the bed movement and engagement of both clutches at the end of such stroke.

15. A printing press according to claim 14 wherein the cam is so shaped that for each one-half revolution thereof, one clutch remains in engagement while the other clutch becomes disengaged and remains out of engagement for the major portion of the half-revolution and is again engaged just prior to the completion of the half-revolution.

16. Structure according to claim 15 wherein said bed is driven by a reciprocable rack, gearing connecting one of said oscillatable gears with said rack, said bed carrying a rack and driving the other of said oscillatable gears, said gearing always driving the one oscillatable gear in a direction opposite to that of the other oscillatable gear.

17. Structure according to claim 16 wherein said cylinder-driving means includes a cylinder-driving member connected to said cylinder so as to drive it, said driving member including a rotatable sleeve upon which both of said oscillatable gears are splined, clutch rings carried by the sleeve for axial movement thereof to engage the respective oscillatable gears, clutch-actuating mechanism comprising a cam carried by the sleeve for revolving movement with the sleeve, and means for rotating said cam to move said clutch rings axially into and out of engage ment with said oscillatable gears.

18. Structure according to claim 17 wherein said means for rotating the cam comprises a constantly driven gear disposed within said sleeve coaxial therewith and mounted for rotation relative thereto, said cam being carried by a shaft disposed radially of the sleeve and rotatably car ried thereby, and a pinion carried by said shaft and engaging said driven gear.

19. Structure according to claim 18 wherein the constantly driven gear is carried by a shaft extending through the trunnion shaft of said cylinder.

20. Structure according to claim 19 wherein said cylinder driving sleeve is disposed at one end of said cylinder and is coaxial with said trunnion shaft.

21. Structure according to claim 20 wherein a driving connection is provided between the sleeve and the cylinder, said connection comprising a roller on one of said members fitting into a radial slot in the other of said members.

References Cited in the file of this patent UNITED STATES PATENTS 

